The present invention relates to an apparatus for generating pulse-width-modulation (PWM) pulses and, more particularly, to a programmable PWM signal generator for selectively generating a plurality of PWM signals each of which having a different pulse width.
PWM pulses are used, for example, in television circuitry, to control the volume, contrast, brightness, color, peaking, tint, treble, bass, balance, etc. Such PWM pulses usually have different pulse widths. In conventional television circuits, in which PWM pulses are required, a microcomputer having interval PWM signal generators is commonly employed. In situations where a weak PWM pulse is output, a digital-to-analog converter integrated circuit is sometimes necessary.
FIG. 1 illustrates a conventional microcomputer 1, which includes internally programmable PWM signal generators to produce signals such as PWM1, PWM2, and PWM3 for controlling the contrast, brightness, and color, respectively of the television. However, the above PWM signal generator is disadvantagous when controlling the above and other various functions of a television. For example, if nine different functions of the television need to be controlled it is difficult to design and manufacture a microcomputer having nine respective internal PWM signal generators. Accordingly, selection of a microcomputer is limited, thus increasing the cost and reducing the reliability of the product.